Shower stall base



FIG. 1 is a perspective view taken from the top, front and left side of a shower stall base showing our new design;

FIG. 2 is a perspective view taken from the bottom rear and right side thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a perspective view taken from the top, front and left side of a modified form of the shower stall base shown in FIG. 1;

FIG. 5 is a perspective view taken from the bottom rear and right side of FIG. 4;

FIG. 6 is a top plan view of FIG. 4;

FIG. 7 is a perspective view of taken from the top, front and left side of a second modified form of the shower stall base shown in FIG. 1;

FIG. 8 is a perspective view taken from the bottom, rear and right side of FIG. 7; and,

FIG. 9 is a top plan view of FIG. 7. 

The ornamental design for shower stall base, as shown and described. 